What happens to the lift created by an airfoil at lower altitudes with low humidity?

The lift generated by an airfoil is influenced by several factors, including air density, humidity, and altitude. At lower altitudes, the density of the air is greater because the air is more compressed. This higher density means that there are more air molecules available for the airfoil to interact with, which increases the lift produced.

When humidity is low, the air is primarily composed of nitrogen and oxygen, which are denser than humid air, which contains water vapor. Water vapor is lighter than the other components of air, so lower humidity translates to a denser air mass. Therefore, the combination of low altitude and low humidity contributes positively to the lift of an airfoil, as the available air density is higher.

Thus, the lift increases due to greater density of air at lower altitudes, which is why this option is the correct choice.